Planet MySQL Planet MySQL: Meta Deutsch Español Français Italiano 日本語 Русский Português 中文
Showing entries 1 to 10 of 41 10 Older Entries

Displaying posts with tag: transactions (reset)

Introduction into storage engine troubleshooting: Q & A
+0 Vote Up -0Vote Down

In this blog, I will provide answers to the Q & A for the “Introduction into storage engine troubleshooting” webinar.

First, I want to thank everybody for attending the July 14 webinar. The recording and slides for the webinar are available here. Below is the list of your questions that I wasn’t able to answer during the webinar, with responses:

  [Read more...]
Q: Does MySQL support ACID? A: Yes
+2 Vote Up -0Vote Down

I was recently asked this question by an experienced academic at the NY Oracle Users Group event I presented at.

Does MySQL support ACID? (ACID is a set of properties essential for a relational database to perform transactions, i.e. a discrete unit of work.)

Yes, MySQL fully supports ACID, that is Atomicity, Consistency, Isolation and Duration. (*)

This is contrary …

  [Read more...]
Configuring and testing MySQL binary log
+0 Vote Up -0Vote Down

The binary log contains “events” that describe database changes. On a basic installation with default options, it's not turned on. This log is essential for accommodating the possible following requirements:

Replication: the binary log on a master replication server provides a record of the data changes to be sent to slave servers. Point in Time recovery: allow to recover a database from a full

MySQL replication in action - Part 3: all-masters P2P topology
+1 Vote Up -0Vote Down

Previous episodes:

MySQL replication in action - Part 1: GTID & CoMySQL replication in action - Part 2 - Fan-in topology


In the …




  [Read more...]
Tracking MySQL query history in long running transactions
+0 Vote Up -0Vote Down

Long running transactions can be problematic for OLTP workloads, particularly where we would expect most to be completed in less than a second. In some cases a transaction staying open just a few seconds can cause behaviour that is entirely unexpected, with the developers at a loss as to why a transaction remained open. There are a number of ways to find long running transactions, luckily versions of MySQL from 5.6 onwards provide some very insightful instrumentation.

  [Read more...]
Improvements for XA in MySQL 5.7
+1 Vote Up -0Vote Down

Today I was doing some tests with XA transactions in MySQL 5.6.

The output of the XA RECOVER command to list transactions was hard to read because of the representation of the data column:

The good news is that 5.7 has transaction information in performance_schema:

mysql> select trx_id, isolation_level, state, xid, xa_state, access_mode 
-> from performance_schema.events_transactions_current; …





  [Read more...]
When your query is blocked, but there is no blocking query - Part 3
+0 Vote Up -0Vote Down

In the previous blog posts I've talked about transactions which block other transactions but don't do anything and about some possible solutions.

In this post I will show you how to get even more information about what is locked by a transaction.

As you might have noticed the information_schema.innodb_locks table doesn't show all locks. This is what the …



  [Read more...]
When your query is blocked, but there is no blocking query - Part 2
+0 Vote Up -0Vote Down

In my previous post I talked about a transaction which blocked other transactions without doing anything. I talked about finding data from the blocking transaction using SYS and performance_schema.

But what are the possible solutions?

The first solution is to (automatically) kill the blocking transactions. Long running transactions can also stall the purging in InnoDB. See …



  [Read more...]
Introducing TokuMX Transactions for MongoDB Applications
+1 Vote Up -1Vote Down

Since our initial release last summer, TokuMX has supported fully ACID and MVCC multi-statement transactions. I’d like to take this post to explain exactly what we’ve done and what features are now available to the user.

But before beginning, an important note: we have implemented this for non-sharded clusters only. We do not support distributed transactions across different shards.

  [Read more...]
How InnoDB works with transactions and auto recovery
+0 Vote Up -0Vote Down

How InnoDB work with transactions:

When any transaction will be completed with COMMIT,  InnoDB will write those changes in InnoDB Buffer Pool. After that InnoDB will run some background operations like checkpoint.  Checkpoint is the most important operation which will writes the changes on disk.   Lets see how it will work.

During the checkpoint phase, InnoDB writes dirty pages to the double write buffer, and then writes pages from the doublewrite buffer to the actual tablespace. During checkpointing, as pages are flushed to the actual …

  [Read more...]
Showing entries 1 to 10 of 41 10 Older Entries

Planet MySQL © 1995, 2016, Oracle Corporation and/or its affiliates   Legal Policies | Your Privacy Rights | Terms of Use

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.